The influence of therapy on CD4+CD25highFOXP3+ regulatory T cells in systemic lupus erythematosus patients: a prospective study

Genetic Variations Controlling Regulatory T Cell Development and Activity in Mouse Models of Lupus-Like Autoimmunity

Immune homeostasis is a constant balancing act between effector T cells and regulatory T cells defined by Foxp3 expression, the transcription factor that drives their differentiation and immunosuppressive activity. Immune homeostasis is altered when Treg cells are not generated or maintained in sufficient numbers. Treg cells rendered unstable by loss of Foxp3 expression, known as ex-Treg cells, gain pro-inflammatory functions. Treg cells may also become dysfunctional and lose their suppressive capabilities. These alterations can cause an imbalance between effector and regulatory subsets, which may ultimately lead to autoimmunity. This review discusses recent studies that identified genetic factors that maintain Treg cell stability as well as preserve their suppressive function. We focus on studies associated with systemic lupus erythematosus and highlight their findings in the context of potential therapeutic gene targeting in Treg cells to reverse the phenotypic changes and functional dysregulation inducing autoimmunity.

Regulatory T cell function in autoimmune disease

Autoimmune diseases are characterized by a failure of tolerance to own body components resulting in tissue damage. Regulatory T cells are gatekeepers of tolerance. This review focusses on the function and pathophysiology of regulatory T cells in the context of autoimmune diseases including rheumatoid and juvenile idiopathic arthritis as well as systemic lupus erythematosus with an overview over current and future therapeutic options to boost Treg function.

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Regulatory T cells are critical mediators of immune tolerance and critically depend on external IL-2.

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Tregs are expanded during inflammation, where the local milieu enhances resistance to suppression in T effector cells.

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Human Tregs are characterized by different markers, which hampers the comparability of studies in patients with autoimmunity.

Effects of hydroxychloroquine on proteinuria in membranous nephropathy

BACKGROUND

Many patients with primary membranous nephropathy have severe proteinuria unresponsive to optimized renin-angiotensin-aldosterone system inhibitors (RAASi). We evaluated the efficacy and safety of hydroxychloroquine as an adjunctive agent in membranous nephropathy (MN) treatments.

METHODS

We prospectively recruited 126 patients with biopsy-proven primary membranous nephropathy and urinary protein 1-8 g/day while receiving optimized RAASi treatment for ≥ 3 months and well-controlled blood pressure. Forty-three patients received hydroxychloroquine and RAASi (hydroxychloroquine-RAASi group), and 83 patients received RAASi alone (RAASi group). Treatment responses, including proteinuria reduction, complete and partial remission rates, and autoantibody against phospholipase A2 receptor (anti-PLA2R) levels, were compared between the two groups at 6 months and over the long term.

RESULTS

At 6 months, the effective response rate (proteinuria reduction > 30%) (57.5% vs. 28.9%, P = 0.002), clinical remission rate (35.0% vs. 15.7%, P = 0.015), and percentage change in proteinuria (- 51.7% vs. - 21.9%, P < 0.001) were higher, and the rate of switching to immunosuppressants (25.0% vs. 45.8%, P = 0.027) was lower in the hydroxychloroquine-RAASi group than in the RAASi group. Hydroxychloroquine administration was an independent protective factor with an effective response (OR 0.37, P = 0.021). In the long term, the clinical remission rate was higher in the HCQ-RAASi group (62.5% vs. 38.6%, P = 0.013). Hydroxychloroquine therapy was associated with a higher rate of anti-PLA2R reduction (< 20 U/ml) (HR 0.28, P = 0.031). We observed no serious adverse events associated with hydroxychloroquine.

CONCLUSIONS

Hydroxychloroquine could be an option for patients with membranous nephropathy seeking to achieve proteinuria reduction and anti-PLA2R antibody reduction in addition to optimized RAASi. Randomized controlled trials are needed to confirm these findings.

TRIAL REGISTRATION

ChiCTR2100045947, 20210430, retrospectively registered.

Effect of systemic steroid therapy in Graves' orbitopathy on regulatory T cells and Th17/Treg ratio

PURPOSE

Glucocorticoids are a mainstay treatment for Graves' orbitopathy, yet their exact mechanisms of action remain unclear. We aimed to determine whether the therapeutic effects of systemic steroid therapy in Graves' orbitopathy are mediated by changes in regulatory T lymphocytes (Tregs) and T helper 17 lymphocytes (Th17).

METHODS

We assessed Treg and Th17 levels in the peripheral blood of 32 patients with active, moderate-to-severe Graves' orbitopathy who received 12 weekly pulses of methylprednisolone, and determined their association with disease severity, disease activity, and treatment outcomes. The acute orbitopathy phase was confirmed based on clinical evaluation and magnetic resonance imaging, and assessed using the clinical activity score (CAS). The severity of the disease was classified according to ETA/EUGOGO guidelines, and quantified based on the total eye score. Treatment response was determined based on specific criteria (e.g., changes in CAS score, diplopia grade, visual acuity, etc.). Treg and Th17 cells were identified using flow cytometry.

RESULTS

Methylprednisolone treatment improved the activity of the disease and altered the Th17/Treg balance (i.e., the percentage of Tregs decreased while the number of Th17 cells remained unchanged). There was no association between the Treg/Th17 ratio and the activity and severity of the disease or the treatment response.

CONCLUSIONS

Therapeutic effects of steroid therapy in Graves' orbitopathy are not mediated by Treg and Th17 alterations in the peripheral blood. The decrease in peripheral Treg percentage is likely a consequence of the non-specific effects of steroids and does not impact clinical outcome.

Short-term prognostic effects of circulating regulatory T-Cell suppressive function and vascular endothelial growth factor level in patients with non-small cell lung cancer and obstructive sleep apnea

OBJECTIVE

To determine if suppressive function of regulatory T-cells (Tregs) and vascular endothelial cell growth factor (VEGF) levels are closely associated with prognosis of patients with non-small cell lung cancer (NSCLC) and obstructive sleep apnea (OSA).

METHODS

Peripheral blood from 20 OSA patients, 44 newly diagnosed NSCLC patients with (n = 22) and without (n = 22) OSA was collected. Forkhead box protien 3 plus (Foxp3⁺) and CTLA-4⁺ Tregs ratio were analyzed with flow cytometry. Levels of VEGF, IL-10 and TGF-β₁ were analyzed with enzyme-linked immuno sorbent assay. NSCLC patients with and without OSA were followed up for two years. Optimal cutoff values were determined by receiver operating characteristic curves. Survival analysis were performed using the Kaplan-Meier test.

RESULTS

NSCLC patients with OSA showed higher Foxp3⁺Tregs ratio, higher plasma VEGF and TGF-β₁ levels when compared with NSCLC patients without OSA (P < 0.05). In NSCLC patients with OSA or not, subjects with higher Foxp3⁺Treg ratio, higher TGF-β₁ and VEGF levels tended to have poor mean survival time and two-year overall survival (OS, Foxp3⁺Treg: 636.7 vs. 704.8 days, 59.0% vs. 82.6%, P = 0.125; TGF-β₁: 637.8 vs. 698.4 days, 57.0% vs. 84.4%, P = 0.054; VEGF: 642.9 vs. 677.5 days, 48.6% vs. 81.3%, P = 0.074). Multivariate Cox regression adjusted for disease stage and receipt of systemic treatments, confirmed the links between high VEGF level and worse OS (HR: 1.003; 95% CI: 1.001-1.005; P = 0.021).

CONCLUSIONS

OSA may up-regulate the expression of circulating TGF-β₁, VEGF and Foxp3⁺Tregs expression in NSCLC patients. Elevated VEGF level is closely associated with worse short-term survival in NSCLC patients with OSA or not.

Modulatory Effect of the Euro-Lupus Low-Dose Intravenous Cyclophosphamide Regimen on Circulating Immune Cells in Systemic Lupus Erythematosus

A Euro-Lupus regimen of low-dose intravenous cyclophosphamide (CFA) is commonly used to treat severe organ manifestations of systemic lupus erythematosus (SLE), particularly lupus nephritis (LN). There are no data on the distributions and dynamics of immune cell populations in patients with various treatment outcomes. The circulating immune cells of 11 female SLE patients were assessed before and after Euro-Lupus regimen (cumulative dose of 3000 mg CFA) by flow cytometry together with those of 16 healthy women. A subanalysis was performed in LN patients who achieved complete remission (CR; n = 3), partial remission (PR; n = 4), and no response (NR; n = 2). In SLE, the Euro-Lupus regimen decreased the percentage and absolute count of B cells; increased the percentage of CD8⁺ T cells, T regulatory cells, neutrophils, and monocyte subsets; and activated T and NK cells compared to healthy controls (P < 0.050). Patients with LN achieving CR had significantly lower proportions of CD27⁺ B memory cells compared to poor responders (PR/NR, P = 0.035). The post-treatment percentages and absolute numbers of B cells, T cells, NK cells, monocytes, and neutrophils showed high inter-individual variability with no association with treatment outcome. Our pilot study revealed the dynamics of changes in immune cell populations in SLE patients during a Euro-Lupus regimen, mainly the lowering of B cells. In LN patients who achieved CR, a lower proportion of CD27⁺ B memory cells was evident compared to poor responders (PR/NR). Further studies on usefulness of monitoring immune cells for treatment response prediction on larger cohorts are needed.

Imbalance between T helper 17 and regulatory T cell subsets plays a significant role in the pathogenesis of systemic sclerosis

Systemic sclerosis (SSc) is a rare autoimmune disease that is characterized by fibrosis, inflammation, and vasculopathy of the skin and internal organs. The etiopathogenesis of SSc remains unclear. However, the pivotal role of T lymphocytes with an aberrant immune response in SSc is well established. Among T cells, IL-17-producing helper T (Th17) cell and regulatory T (Treg) cell subsets have recently been found to play crucial roles in SSc pathogenesis. Generally speaking, Th17 cell subsets up-regulate inflammation, fibrosis, and autoimmunity, which are present in SSc, while Treg cell subsets have an immunosuppressive function and resist the immunological performance of Th17 cells. Up-to-date evidence has pointed out that the imbalance and abnormal functions of Th17/Treg cells may contribute to SSc. Therefore, this review aims to summarize the current understanding of the vital cytokines and signaling pathways that are involved in Th17/Treg differentiation and functions, and their roles in the pathogenesis of SSc, thus providing novel insights about targeting the Th17/Treg balance as a potential therapy for SSc treatment in the near future.

A DNA-Methylated Sight on Autoimmune Inflammation Network across RA, pSS, and SLE

Methylation variabilities of inflammatory cytokines play important roles in the development of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and primary Sjögren's syndrome (pSS). With heightened focus on personalized and precise medicine, it is necessary to compare and contrast the difference and similarity of cytokine methylation status between the 3 most classic autoimmune diseases (AIDs). In this study, we integrated 5 Cytokine-Chips from genome-wide DNA methylation datasets of the 3 kind of AIDs, delta-beta value was calculated for intergroup difference, and comprehensive bioinformatics analyses of cytokine genes with aberrant methylations were performed. 125 shared differential methylation variabilities (DMVs) were identified. There were 102 shared DMVs with similar methylation status; 3 hypomethylated differential methylation regions (DMRs) across the AIDs were found, and all 3 DMRs were hypomethylated. DMRs (AZU1, LTBR, and RTEL1) were likely to serve as activator in the inflammatory process. Particularly, AZU1 and LTBR with hypomethylated TSS and first exon located in the promoter regions were able to trigger inflammation signaling cascades and play critical roles in autoimmune tautology. Moreover, functional epigenetic module (FEM) algorithm showed that different inflammatory networks are involved in different AIDs; 5 hotspots were identified as biologically plausible pathways in inducing or perpetuating of inflammation which are epigenetically deregulated in AIDs. We concluded methylation variabilities among the same cytokines can greatly impact the perpetuation of inflammatory process or signal pathway of AIDs. Differentiating the cytokine methylation status will serve as valuable resource for researchers alike to gain better understanding of the epigenetic mechanisms of the three AIDs. Even more importantly, better understanding of cytokine methylation variability existing between the three classic AIDs will aid in identification of potential epigenetic biomarkers and therapeutic targets. This trial is registered with ChiCTR-INR-16010290, a clinical trial for the treatment of rheumatoid arthritis with Warming yang and Smoothening Meridians.

Effect of TGF-β1 on blood CD4+CD25high regulatory T cell proliferation and Foxp3 expression during non-small cell lung cancer blood metastasis

Metastatic circulating tumor cells in non-small cell lung cancer (NSCLC) metastasis have been reported to be associated with an immune response. The present study aimed to provide a theoretical basis for the immunomodulatory processes during NSCLC blood metastasis. NSCLC blood and normal peripheral blood mononuclear cells (PBMCs) were collected. The quantity of cluster of differentiation (CD)4⁺CD25^high regulatory T (Treg) cells and the intracellular forkhead box protein 3 (Foxp3) expression in CD4⁺CD25^high Treg cells were determined by flow cytometry. Furthermore, the effect of transforming growth factor β1 (TGF-β1) on NSCLC blood CD4⁺CD25⁺ Treg cell proliferation was explored by activating blood mononuclear cells with an anti-CD3 monoclonal antibody, interleukin-2 and different doses of TGF-β1. Reverse transcription-quantitative polymerase chain reaction assays were used to detect the mRNA expression of Foxp3. Carboxyfluorescein succinimidyl ester staining was used to analyze the proliferation dynamics of lymphocyte subsets. Results indicate that the proportion of CD4⁺ T cells in the blood of patients with NSCLC was significantly higher compared with normal peripheral blood (P<0.01). Foxp3 expression in NSCLC blood Treg cells was significantly decreased compared with normal peripheral blood (P<0.01). NSCLC blood mononuclear cells treated with TGF-β1 at 1, 5 and 25 ng/ml significantly induced Foxp3 expression in CD4⁺CD25⁺ Treg cells compared with the control group (P<0.05). The proportion of CD4⁺CD25⁺ Treg and CD8⁺ T cells were elevated in generation 6, 7, 8 after 6 days of TGF-β1 treatment compared with untreated cells. The proportion of CD4⁺CD25⁺ Treg and CD8⁺ T cells were elevated in generation 8, 9 and with TGF-β1 treatment after 8 days compared with untreated cells. These results indicate that CD4⁺CD25⁺ Treg cells proliferate at a greater rate compared with CD8⁺ T cells after 4, 6 or 8 days of treatment. The proportion of CD4⁺CD25^high Treg cells in NSCLC blood was significantly higher (P<0.05) compared with normal peripheral blood. The number of Foxp3⁺ T cells was significantly lower (P<0.05) compared with normal peripheral blood. The data presented in this study suggest that NSCLC blood CD4⁺CD25^high Treg cells are functionally immature and that TGF-β1 may promote maturation.

Analysis of FOXP3+ regulatory T cell subpopulations in peripheral blood and tissue of patients with systemic lupus erythematosus

Regulatory T cells (Tregs) are critical mediators of immune tolerance, yet their involvement in the autoimmune disease systemic lupus erythematosus (SLE) is incompletely understood. We analyzed CD4⁺ T cell subpopulations with Treg-related phenotypes and their association with disease activity in peripheral blood (PB) and tissues of patients with SLE. In detail, we quantified subpopulations regarding CD25, FOXP3, CD62L, CCR6, CD27, CD45RA, and CD45RO expression in PB from 31 patients with SLE divided into two disease activity groups and 32 healthy controls using flow cytometry. CD4⁺ and FOXP3⁺ T cells in skin and kidney biopsies of patients with SLE were quantified by immunohistochemistry. CD4⁺CD25^+/++FOXP3⁺ and CD4⁺CD25⁺CD45RA^-/CD45RO⁺ T cell frequencies were significantly higher in PB from patients with active compared to inactive SLE. The fraction of CD4⁺CD25⁺⁺FOXP3⁺ Tregs and CD4⁺CD25⁺CD45RA⁺/CD45RO^- naïve Tregs was not significantly different between these groups. CD4⁺CD25⁺⁺ Tregs from active SLE patients comprised significantly less CD27⁺ cells and more CCR6⁺ cells compared to patients with inactive SLE. The percentage of CD4⁺FOXP3⁺ T cells among inflammatory infiltrates in skin and kidney biopsies of SLE patients was not different from other inflammatory skin/kidney diseases. In conclusion, although CD4⁺FOXP3⁺ T cell frequencies in the inflamed tissues of SLE patients were comparable to other inflammatory diseases, distinct T cell subpopulations appeared misbalanced in PB of patients with active SLE. Here, cells phenotypically resembling activated T cells, but not Tregs, were increased compared to patients with inactive SLE. Within Tregs of patients with active SLE, markers related to Treg function and homing were altered.

Effect of induction therapy on circulating T-helper 17 and T-regulatory cells in active proliferative lupus nephritis

INTRODUCTION

T-helper 17 (Th17) cells and T-regulatory (Treg) cells have been suggested to play pathogenic roles in lupus nephritis. The in vivo effects of current therapies for lupus nephritis (LN) on these cells have not been adequately studied.

METHODS

We conducted a prospective observational study among patients with active proliferative lupus nephritis (LN) who received Eurolupus induction therapy and assessed them as per the European League Against Rheumatism criteria for renal response. Peripheral circulatory Th17 and Treg cell numbers were enumerated at start of therapy, at 3 and 6 months follow-up periods using flow cytometry. Baseline values were compared with inactive lupus patients (iSLE) and healthy controls (HC).

RESULTS

Thirty patients with LN, 20 iSLE and 22 HC were enrolled into the study. In LN, Th17 frequency was significantly higher compared to HC, and Treg frequency significantly lower compared to both iSLE and HC. Nineteen patients fulfilled criteria for response (partial or complete) at 6 months. Responder group showed a significant decline in Th17 frequency and an increasing trend in Treg frequency compared to baseline after 6 months of therapy.

CONCLUSION

Circulating Th17 cells were significantly raised in patients with active proliferative LN and showed a significant reduction in responder patients following therapy.

Regulatory T cells in multiple sclerosis and myasthenia gravis

Multiple sclerosis (MS) is a chronic debilitating disease of the central nervous system primarily mediated by T lymphocytes with specificity to neuronal antigens in genetically susceptible individuals. On the other hand, myasthenia gravis (MG) primarily involves destruction of the neuromuscular junction by antibodies specific to the acetylcholine receptor. Both autoimmune diseases are thought to result from loss of self-tolerance, which allows for the development and function of autoreactive lymphocytes. Although the mechanisms underlying compromised self-tolerance in these and other autoimmune diseases have not been fully elucidated, one possibility is numerical, functional, and/or migratory deficits in T regulatory cells (Tregs). Tregs are thought to play a critical role in the maintenance of peripheral immune tolerance. It is believed that Tregs function by suppressing the effector CD4+ T cell subsets that mediate autoimmune responses. Dysregulation of suppressive and migratory markers on Tregs have been linked to the pathogenesis of both MS and MG. For example, genetic abnormalities have been found in Treg suppressive markers CTLA-4 and CD25, while others have shown a decreased expression of FoxP3 and IL-10. Furthermore, elevated levels of pro-inflammatory cytokines such as IL-6, IL-17, and IFN-γ secreted by T effectors have been noted in MS and MG patients. This review provides several strategies of treatment which have been shown to be effective or are proposed as potential therapies to restore the function of various Treg subsets including Tr1, iTr35, nTregs, and iTregs. Strategies focusing on enhancing the Treg function find importance in cytokines TGF-β, IDO, interleukins 10, 27, and 35, and ligands Jagged-1 and OX40L. Likewise, strategies which affect Treg migration involve chemokines CCL17 and CXCL11. In pre-clinical animal models of experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune myasthenia gravis (EAMG), several strategies have been shown to ameliorate the disease and thus appear promising for treating patients with MS or MG.

CD4(+)CD25(hi)Foxp3(+) Cells Exacerbate Bleomycin-Induced Pulmonary Fibrosis

Idiopathic pulmonary fibrosis is a fatal lung disease with a median survival of 2 to 5 years. A decade of studies has downplayed inflammation contributing to its pathogenesis. However, these studies preceded the discovery of regulatory T cells (Tregs) and all of their functions. On the basis of human studies demonstrating Tregs can decrease graft-versus-host disease and vasculitides, there is consideration of their use to treat idiopathic pulmonary fibrosis. We hypothesized that Treg therapy would attenuate the fibroplasia involved in a preclinical murine model of pulmonary fibrosis. IL-2 complex was used in vivo to expand CD4(+)CD25(hi)Foxp3(+) cells in the lung during intratracheal bleomycin challenge; however, this unexpectedly led to an increase in lung fibrosis. More important, this increase in fibrosis was a lymphocyte-dependent process. We corroborated these results using a CD4(+)CD25(hi)Foxp3(+) cellular-based therapy. Mechanistically, we demonstrated that CD4(+)CD25(hi)Foxp3(+) cells undergo alterations during bleomycin challenge and the IL-2 complex had no effect on profibrotic (eg, transforming growth factor-β) or type 17 immune response cytokines; however, there was a marked down-regulation of the type 1 and augmentation of the type 2 immune response cytokines from the lungs. Collectively, our animal studies show that a specific lung injury can induce Treg alterations, which can augment pulmonary fibrosis.

Regulatory T Cell Responses to High-Dose Methylprednisolone in Active Systemic Lupus Erythematosus

BACKGROUND/PURPOSE

A slight increase in the proportion of circulating regulatory T (Treg) cells has been reported in systemic lupus erythematosus (SLE) patients taking oral prednisone. The effects of intravenous (IV) high dose methylprednisolone (MP) on Tregs have not yet been described, especially in active SLE.

METHODS

We prospectively analyzed the proportion of circulating CD4+ Treg cell subsets defined as follows: (1) naïve Treg (nTreg) FoxP3lowCD45RA+ cells; (2) effector Treg (eTreg) FoxP3highCD45RA- cells; and (3) non-suppressive FoxP3lowCD45RA- cells (non-regulatory Foxp3low T cells). Peripheral blood mononuclear cells of patients with active SLE were analyzed before the first infusion of IV high dose MP (day 0) and the following days (day 1, day 2, ±day 3 and ±day 8). The activity of SLE was assessed by the SLEDAI score.

RESULTS

Seventeen patients were included. Following MP infusions, the median (range) percentage of eTregs significantly increased from 1.62% (0.53-8.43) at day 0 to 2.80% (0.83-14.60) at day 1 (p = 0.003 versus day 0), 4.64% (0.50-12.40) at day 2 (p = 0.06 versus day 1) and 7.50% (1.02-20.70) at day 3 (p = 0.008 versus day 2), and declined to baseline values at day 8. Expanding eTreg cells were actively proliferating, as they expressed Ki-67. The frequency of non-regulatory FoxP3low T cells decreased from 6.39% (3.20-17.70) at day 0 to 4.74% (1.03-9.72) at day 2 (p = 0.005); nTreg frequency did not change. All patients clinically improved immediately after MP pulses. The absence of flare after one year of follow up was associated with a higher frequency of eTregs at day 2.

CONCLUSION

IV high dose MP induces a rapid, dramatic and transient increase in circulating regulatory T cells. This increase may participate in the preventive effect of MP on subsequent flares in SLE.